Patients were followed for a maximum of 192 weeks; all patients were to receive ddI, EFV, and FTC together once daily. Study visits occurred at study entry, Weeks 2,and 4, and every 4 weeks thereafter. Blood collection, medical history assessment, and a physical exam occurred at all visits; urine collection occurred at selected visits. Intensive pharmacokinetic (PK) studies was done at Weeks 2 and 12 to determine if dose adjustments were required for any of the drugs. If virologic failure was determined, PK studies was repeated 4 weeks after adjustments in therapy. Parents or guardians were asked to complete treatment adherence questionnaires at some visits. Some patients were also asked to participate in an additional PK study after Week 16 or week 96.